Lethariella is a genus of fruticose lichens in the family Parmeliaceae. The genus was originally proposed as a subgenus of Usnea by Polish lichenologist Józef Motyka in his 1936 monograph of that genus. Norwegian botanist Hildur Krog elevated the taxon to generic status in 1976. Three species of Lethariella are used by ethnic peoples of Yunnan Province (China) as a component of purported health-promoting tea: Lethariella cashmeriana, L. sernanderi, and L. sinensis.